Negative pressure control apparatus for brake booster

• US 6,283,559 B1
• Filed: 04/21/1999
• Issued: 09/04/2001
• Est. Priority Date: 06/02/1998
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Yamada, Yoshihisa, Endo, Hiroaki, Watanabe, Ryochi
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): NGUYEN, XUAN LAN T
• Application Number:
  US09/295,355
• Time in Patent Office: 867 Days
• Field of Search: 303/113.3, 303/144, 303/24.1, 303/192, 303/191, 303/193
• US Class Current: 303/113.3
• CPC Class Codes: B60T 13/46 Vacuum systems
• CPC Class Codes: B60T 17/02 Arrangements of pumps or compressors, or control devices therefor
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18
• CPC Class Codes: F02D 41/3076 with special conditions for selecting a mode of combustion, e.g. for starting, for diagnosing

Abstract

A negative pressure control apparatus for a brake booster is provided which can always maintain a required negative pressure in a negative pressure chamber of the brake booster in a system including a direct-injection engine. The apparatus has a brake operation predicting part for predicting execution of a brake operation by a driver. When execution of a brake operation is predicted, negative pressure in the negative pressure chamber is controlled to be a required value.

Claims

1. A negative pressure control apparatus for a brake booster in a vehicle for controlling negative pressure in a negative pressure chamber of the brake booster connected to an intake pipe of a direct-injection engine at a position downstream of a valve in the intake pipe, comprising:

a brake operation predicting part for predicting execution of a brake operation by a driver; and

a booster negative pressure controller for controlling the negative pressure in said negative pressure chamber to be a required value when execution of a brake operation is predicted under a condition in which the negative pressure is smaller than a predetermined value.

2. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said brake operation predicting part predicts execution of a brake operation when the vehicle is running on a downhill road.

3. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said brake operation predicting part predicts execution of a brake operation when the vehicle behavior control is being performed.

4. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said brake operation predicting part predicts execution of a brake operation when a between-car time to another vehicle running ahead is smaller than a predetermined value.

5. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said brake operation predicting part predicts execution of a brake operation when position information is transmitted indicating that the vehicle is running towards a crossing or a free way exit.

6. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said brake operation predicting part predicts execution of a brake operation when a shift-down operation is performed by the driver.

7. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said brake operation predicting part predicts execution of a brake operation when a depression of an accelerator pedal is being released faster than a predetermined value.

8. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said brake operation predicting part predicts execution of a brake operation when a shift lever is in a neutral position or a select lever is in an N range.

9. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said negative pressure controller controls the negative pressure by changing an opening of said valve.

10. The negative pressure control apparatus for a brake booster as claimed in claim 9, further comprising:

a mode determining part for, when said negative pressure controller changes the opening of the valve while the engine is operating in a stratified charge combustion mode, determining whether or not the stratified charge combustion mode can be maintained; and

a mode switching part for switching the operation mode of the engine to a stoichiometric combustion mode when said mode determining part determines that the stratified charge combustion mode cannot be maintained.

11. The negative pressure control apparatus for a brake booster as claimed in claim 1, wherein said required value is determined based on the vehicle speed.